System for fluid containment and venting

ABSTRACT

Systems and methods for controlling subterranean fluid flow. The system utilizes a fluid impervious geotextile material comprising geotextile fabric having a polymeric material thereon, and a fluid distribution system comprising an array of perforated pipes in fluid communication with a vent. The system may include a plurality of geotextile anchors.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 61/600,853, filed Feb. 20, 2012, entitled “GEOTEXTILE FABRIC AND RIGID POLYUREA OR POLYURETHANE COATINGS WITH VENTING,” which application is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention is directed to materials and systems for control of subterranean fluids. In particular, the present invention relates to systems that utilize a geotextile fabric with a polymeric material.

BACKGROUND OF THE INVENTION

Geotextile fabrics have many applications, such as for roads, airfields, railroads, embankments, retaining walls and other structures, construction silt fences, reservoirs, canals, dams, and coastal engineering projects such as mitigating shoreline erosion sand dune armoring to protect upland coastal property from storm surge, wave action and flooding.

Geotextile fabrics and systems incorporating such are commonly used to retain soil, rocks and other geological materials. Geotextile fabrics and systems are also commonly used to retain (e.g., contain) liquids to inhibit contamination of soil and ground water, such as in liquid manure lagoons.

SUMMARY

Unlike conventional uses of geotextile fabrics, the present invention contains and controls the flow of liquids and gases. The system of the present invention inhibits the mixing of two different fluid streams in, into and out from the ground. For example, the system can inhibit the mixing or commingling of two gases (e.g., oxygen and methane), and/or can inhibit the mixing or commingling of a gas with a liquid (e.g., methane and water). The system also includes a fluid distribution system of diversion, collection and venting of fluid.

This disclosure describes a system that utilizes a lateral expanse of geotextile fabric in combination with a polymeric barrier, and an array of pipes, vents, and/or drains to divert, collect and vent fluids.

A first particular embodiment of this invention is a system for controlling subterranean fluid flow. The system includes a fluid impervious geotextile sheet material comprising geotextile fabric having a first side and a second side. The geotextile sheet material has a continuous polymeric material thereon, the polymeric material optionally being on the second side of the geotextile fabric. The system also includes a fluid distribution system comprising an array of perforated pipes in fluid communication with a vent. When the system is installed, the fluid impervious geotextile sheet material laterally extends on or under the surface of the ground with the first side of the geotextile sheet material more subterranean than the second side. The array of perforated pipes is located under the geotextile sheet material at a location to collect and vent volatile gases captured under the fluid impervious geotextile sheet material. The system may include a plurality of geotextile anchors.

A second particular embodiment of this invention is a method of controlling fluid flow in ground. The method comprising installing a system over a laterally extensive expanse of ground, optionally covering at least a portion of the system with ballast, collecting fluids from the ground in the fluid distribution system of the system; and venting collecting gases and draining collected liquid. The system may be any of the systems described herein.

Another particular embodiment of this invention is a system for controlling subterranean fluid flow that comprises a liquid impervious geotextile material composed of geotextile fabric having a polymeric material thereon (optionally a continuous polymeric material), the polymeric material being on either the top side or the bottom side of the fabric. The system also has a fluid distribution system of an array of perforated pipes in fluid communication with a vent. When the system is installed in a laterally extensive subterranean application, at least a portion of the fluid distribution system is in close proximity to the bottom side of the geotextile material. The geotextile material may be impervious to both liquid and gas therethrough. The system may include a plurality of geotextile anchors.

And another particular embodiment of this invention is a system for controlling subterranean fluid flow that comprises a fluid impervious geotextile sheet material comprising geotextile fabric having a first major surface and a second major surface, the geotextile material having a polymeric material layer thereon (optionally a continuous polymeric material), and a fluid distribution system comprising an array of perforated pipes in fluid communication with a vent. The fluid impervious geotextile sheet material laterally extends on or under the surface of the ground. Further, the fluid distribution system is located under the fluid impervious geotextile sheet material at a location to collect and vent volatile gases captured under the fluid impervious geotextile sheet material.

In some embodiments, the geotextile fabric comprises polypropylene. The geotextile fabric may be woven or non-woven. The polymeric material may be polyurethane or polyurea, such as an aromatic polyurea. The polymeric material may have a thickness of at least 1000 micrometers or at least 1500 micrometers, and may be at least partially impregnated into the geotextile fabric.

In some embodiments, the geotextile material is configured to provide a sloped surface, with a portion of the fluid distribution system located at a top or upper elevation portion of the sloped surface and under the geotextile material. The fluid distribution system can include a drainage trench in fluid communication with the array of perforated pipes. There may be geotextile fabric wrapped around the array of perforated pipes. The vent may have a one-way valve or a safety release valve, and may include a wind powered venting system.

These and various other features and advantages will be apparent from a reading of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWING

The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawing, in which:

FIG. 1 is a top plan view of a system of the invention.

FIG. 2 is a cross-sectional side view of the system of FIG. 1 taken along line A-A.

FIG. 3 is an enlarged view of a portion of FIG. 2.

FIG. 4 is a perspective view of a pipe from the fluid diversion, collection and venting system of the system of FIG. 1.

FIG. 5 is a cross-sectional end view of a portion of the system of FIG. 1.

FIG. 6 is a top plan view of a system of the invention.

FIG. 7 is a cross-sectional side view of the system of FIG. 6, and includes an enlarged view of a portion of the system.

FIG. 8 is an enlarged view of a portion of FIG. 7.

FIG. 9 is another enlarged view of a portion of FIG. 7.

FIG. 10 is a side view of a portion of a fluid distribution system of this invention.

FIG. 11 is an enlarged view of a portion of FIG. 10.

FIG. 12 is an enlarged view of a portion of FIG. 10.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure provides systems for containing and controlling the flow of fluids in, into and out from the ground. In some embodiments, the systems inhibit the seepage of liquid (e.g., water) into the ground, thus inhibiting mixing of the liquid and any gases present therein with liquid or gases already present in the ground. In other embodiments, the systems inhibit outflux of gas from the ground.

In the following description, reference is made to the accompanying drawing that forms a part hereof and in which are shown by way of illustration at least one specific embodiment. The following description provides additional specific embodiments. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense. While the present invention is not so limited, an appreciation of various aspects of the invention will be gained through a discussion of the example provided below.

Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties are to be understood as being modified by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

As used herein, the singular forms “a”, “an”, and “the” encompass embodiments having plural referents, unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.

Referring to FIG. 1, a top plan view of an installed system of the present invention is shown. System 10 is installed at or below grade (i.e., at or sub-surface) at a generally laterally extensive orientation; see FIG. 2, where system 10 is positioned on ground 100. System 10 includes a geotextile fabric with a polymeric material, and a fluid distribution system composed of an array of pipes, vents, and/or drains that divert, collect and/or vent the liquid and/or gas to and/or from and/or within ground 100.

Referring to all of FIGS. 1, 2 and 3, system 10 has an expanse of geotextile material or geotextile sheet material 12 (composed of geotextile fabric with polymeric material), in this embodiment, crisscrossed with an array of fluidly interconnected pipes 14. In the illustrated embodiment, the array is an orderly array with essentially regularly and evenly spaced pipes 14, whereas in alternate embodiments pipes 14 may be irregularly spaced or arranged. Best seen in FIGS. 1 and 3, pipes 14 terminate at a peripheral trench 16. Venting pipes 18, which will be discussed further below, provide gaseous communication between the lower side of installed geotextile material 12 (i.e., the side against ground 100) and the upper side of geotextile material 12. Together, pipes 14, trench 16 and vents 18 form a fluid distribution system.

Geotextile material 12 is a fluid impervious material and may be positioned completely above grade-level (i.e., above ground 100) or may be partially or completed covered with ballast. For purposes of the present disclosure, ballast material is any material suitable to provide coverage of the fluid impervious geotextile sheet material 12. Examples of ballast material include clean fill, dirt, sand, rock, gravel, and the like. Anchors 15, selected to suit the site conditions and geotextile material 12, may be used to better secure geotextile material 12 onto and into ground 100. In FIGS. 2 and 3, it can be seen that geotextile material 12 and system 10 extend laterally and are not truly horizontal, but generally horizontal and follow the topography of ground 100. In some embodiments, at least a portion of geotextile material 12 and pipes 14 are oriented at an incline or slope (e.g., about 2-5%) to direct gas to pipes 14 and vents 18. Vents 18 are preferably located at or near high locations in the sloped surface.

FIGS. 4 and 5 provide a better view of the fluid distribution system, particularly of pipes 14. At least some of pipes 14 of system 10 are perforated, to allow fluid flow from the external side of pipe 14 (i.e., from ground 100) to the internal side. Referring to FIG. 4, pipe 14 has a body 40 defining an internal channel 42 though which fluid can flow. Body 40 includes apertures 41 (e.g., perforations) therethrough to allow fluid (i.e., liquid and/or gas) to pass through body 40 into channel 42. Pipes 14 collect fluid (i.e., gas and/or liquid) that diffuse or flow through ground 100 to pipes 14. Once inside channel 42, pipes 14 provide a path of least (or lesser) resistance for fluid flow. Examples of suitable pipes are often called “drain tiles”.

Pipes 14 may be rigid or flexible, and in FIGS. 4 and 5 are illustrated a circular, although other configurations may be used; for example, pipes 14 may have an oval, elliptical, hexagonal, rectangular, or other such cross-sectional shape. Preferably, pipe 14 has a cross-sectional shape that is oval or circular and has a constant inner diameter and a constant outer diameter. Optionally, pipes 14 may have a varying diameter. However, pipes 14 of non-regular shape require extra care in positioning in the system of the present invention to provide appropriate flow of the fluid channeled therein. Pipes 14 are typically formed from PVC, but may from other materials such as nylon, polyethylene (high density or low density), polycarbonate, metal, ceramic, etc. In most embodiments, body 40 of pipes 14 is solid, with apertures 41 for providing fluid flow into channel 42. In a preferred embodiment, apertures 41 have an average diameter or largest dimension of 0.5-2 cm, or alternately, have an average area of about 0.8-3 cm². In alternate embodiments, pipes made from a fluid permeable material, e.g., having a woven or non-woven construction, thus eliminating the need for apertures, can be used.

Pipes 14 are arranged in an array under the expanse of geotextile material 12 (see FIG. 1) with geotextile material 12 positioned above pipes 14 when installed (see FIG. 5). Pipes 14 may be clamped or otherwise secured to ground 100 to inhibit shifting. A fabric or other material permeable to fluid may be positioned (e.g., wrapped) around pipes 14 to allow fluid to pass to into channel 42 through body 40 via apertures 41 yet inhibit dirt and rocks from entering internal channel 42. Pipes having a woven or non-woven construction may be used without wrapping. Pipes 14 may be positioned above the level of geotextile material 12 on ground 100, as illustrated in FIG. 5, to facilitate collection of gas from ground 100. Perforated pipes 14 direct the fluid to a collection area, such as to trench 16 for liquid (FIGS. 1 and 3) or to vent 18 for gas (FIG. 3).

FIGS. 6 through 9 illustrate a second embodiment of a system according to this invention. Unless indicated otherwise, like features of the second system 20 are the same or similar to the features of system 10. Similar to system 10, system 20 of FIGS. 6 through 9 is installed at or below grade level of ground 100, however this system 20 is more sloped than system 10; see FIG. 7. System 20 includes a geotextile fabric with a polymeric material, and a fluid distribution system composed of an array of pipes, vents, and/or drains to divert, collect and/or vent liquid and/or gas from ground 100.

Referring to all of FIGS. 6, 7, 8 and 9, system 20 has an expanse of geotextile material 22 (composed of geotextile fabric 22A with polymeric material 22B) crisscrossed with an array of fluidly interconnected pipes 24 that extend to a peripheral trench 26 which connects to a spoon drain 27. Venting pipes 28 provide gaseous communication between the lower side of installed geotextile material 22 (i.e., the side against ground 100) and the upper side of geotextile material 22. Together, pipes 24, trench 26, drain 27 and vents 28 form a fluid distribution system that provides controlled release of fluid from under geotextile material 22. System 20 includes a gas probe 30 positioned within ground 100 below geotextile fabric 22A and polymeric material 22B to monitor the level of gas (e.g., oxygen, methane) within ground 100.

At least a portion of geotextile material 22 and pipes 24 are preferably oriented at an incline or slope (e.g., about 5%, or about 10%) to provide a sloped surface to direct gas to pipes 24 and vents 28 and direct liquid to pipes 24, trench 26 and drain 27. Gas collected via pipes 24 is vented out from under system 20 by vents 28, which may release the gas into the atmosphere or may direct the gas to a collection system. Liquid collected via pipes 24 is collected in spoon drain 27, which includes an elongate channel or gutter into which pipes 24 drain, in this embodiment, via a one-way drain valve 29 see in FIG. 8 or other hydrostatic valve. One-way drain valve 29 may be wrapped in geotextile fabric or other material to inhibit dirt and rocks from entering valve 29. Spoon drain 27 may include multiple drain valves 29, spaced along the length of the channel or gutter. Liquid collected in spoon drain 27 can be drained, for example, to a liquid collection reservoir or to a treatment facility.

Similar to geotextile material or geotextile sheet material 12, geotextile material or geotextile sheet material 22 may be positioned completely above grade-level (i.e., above ground 100) or may be partially or completed covered with dirt, rocks, or other ground-like material. Preferably, geotextile fabric 22A is proximate ground 100. Anchors 25 may be used to better secure geotextile material 22 into and onto ground 100.

As indicated above, gas collected via pipes 14, 24 is vented from under system 10, 20 by vents 18, 28 through which the gas may be released into the atmosphere or collected. Depending on the gas, it may be beneficial, both environmentally and economically, to collect and further process the gas. For example, methane gas can be collected and harvested to provide heat or to power turbines for electricity.

Vents 18, 28 may include a one-way valve to inhibit reverse flow of gas into ground 100. Vents 18, 28 may include a controllable release valve to avoid excess gas build up within ground 100. A controllable release valve, which can be opened and closed on demand, may be desired around areas where persons may frequent (e.g., close to a work area) or where the exhausting gas or fire poses a risk to nearby items, such as equipment, workshops, storage or tanks (e.g., fuel tanks), etc., for example, if the gas were to ignite. Additionally or alternatively, vents 18, 28 may include a safety release or over-pressurization valve, which automatically opens if the pressure reaches a critical pressure.

FIGS. 10 through 12 illustrate a specific embodiment of a portion of the fluid distribution system of this invention, particularly, a vent pipe 80 in fluid connection with perforated drain pipe 14, 24. Vent pipe 80 has a body 82 having a first end 81 connected to pipe 14, 24 to receive gas from pipe 14, 24 and a second open end 83 as an exit for gas from vent pipe 80. Body 82 can have a hooked configuration turned down towards ground 100 when installed, to inhibit entrance of rain, snow and debris or the like into vent pipe 80 through end 83.

Positioned at end 83 is a venting system facilitate extraction of gas through pipe by increasing suction within pipe 80. A fan assembly 85 includes a blade assembly 86 driven by external air flow (e.g., wind). The illustrated fan assembly 85 includes pedals or cups 88 configured to catch air flow and rotate blade assembly 86. In other embodiments, blade assembly 86 may be electrically powered and/or have a manual rotation feature. Fan assembly 85 may be permanently or removably attached to vent pipe 80 in any suitable manner.

Venting systems such as fan assembly 85 increase the suction within pipes 24 of the fluid distribution system, providing easier removal of gas from system 20. Systems including venting system can utilize less slope or incline of geotextile material 22 than systems that utilize unassisted vents.

System 10, 20 extends across any area of ground 100 from which fluid movement (either into ground 100, within ground 100, or out from ground 100) is to be controlled. For example, system 10, 20 can inhibit the seepage of water into ground 100. As another example, system 10, 20 can inhibit the diffusion of oxygen into ground 100. As yet another example, system 10, 20 can inhibit the diffusion of methane out from ground 100. Each of these objectives is obtains by the liquid and gas impervious geotextile material 12, 22.

System 10, 20 may cover, for example, at least acre (about 4,047 square meters) of ground 100, at least ten acres (about 40,470 square meters) of ground 100, and in some embodiments one hundred or more acres (about 404,700 or more square meters). As a specific example, system 10, 20 may cover an area as large as 75 acres (about 300,000 square meters). For large installations, one system 10, 20 may be used to cover the desired area, or multiple systems 10, 20 can be used to together cover the desired area. Any seams present between multiple systems or in the geotextile fabric or the polymeric material are preferably fluid impermeable, to provide a continuous fluid impermeable material. A seamless fabric is actually preferred.

As indicated above, the system of the present invention utilizes a geotextile fabric 22A and a polymeric material 22B, either as a combination with the geotextile fabric or as coating on the geotextile fabric, that forms geotextile material 22 that is impervious to gas and liquid flow therethrough. The polymeric material may be, for example, polyurea or a polyurethane.

Geotextile fabrics are gas and liquid permeable (i.e., fluid permeable) fabrics which have the ability to separate, filter, reinforce, protect, and/or drain soil, rocks, and other geological structure. Geotextile fabrics come in three basic forms: woven, non-woven needle punched, and non-woven heat bonded. Geotextiles have many known applications and currently support many applications including roads, airfields, railroads, embankments, retaining walls and other structures, reservoirs, canales, dams, coastal engineering such as mitigating shoreline erosion, sand dune armoring to protect upland coastal property from storm surge, wave action and flooding, and construction site silt fences.

Polypropylene is a preferred material for geotextile fabric for the systems of this invention, because it is resistant to commonly encountered soil chemicals, mildew and insects, is UV resistant, and is non-biodegradable. Polypropylene is stable at a pH of 2 to 13. Other polymeric materials, such as polyester, may alternately be used for geotextile fabrics of this invention.

Two specific examples of suitable geotextile fabric for the systems of this invention are commercially available from Nukote Coating Systems International under the trade designations “Nukote GT 20” and “Nukote GT 45”. GT 20 is a polypropylene woven fabric, and GT 45 is a polypropylene non-woven needle punched fabric. Both are stabilized to resist degradation due to UV exposure. Both Nukote GT 20 and Nukote GT 45 meet the following minimum average rolls values:

TABLE 1 Grab tensile (ASTM D 4632) 1.40 kN Grab elongation (ASTM D 4632) 15% Wide width tensile (ASTM D 4595) 35/35 kN/m Wide width elongation (ASTM D 4595) 12/8%   Mullen burst (ASTM D 3786) 5.516 MPa Puncture (ASTM D 4833) 0.622 kN Trapezoidal tear (ASTM D 4533) 0.556 kN UV resistance (ASTM D 4355) 80% at 500 hours AOS (ASTM D 4751) 0.425 mm Permittivity (ASTM D 4491) 0.70/sec Flow rate (ASTM D 4491) 2035 L/min/m²

Other suppliers of geotextile fabric include Granite Environmental Inc., Layfield Materials, U.S. Fabrics Inc., and U.S. Construction Fabrics LLC.

As indicated above, the geotextile fabric is used in combination with a polymeric material or with a polymeric coating on the geotextile fabric. In preferred embodiments, the geotextile fabric is positioned against ground 100 with the polymeric material present on the other side; in other words, the geotextile fabric is positioned between ground 100 and the polymeric material. When geotextile fabric used ‘in combination with’ polymeric material, what is meant is that a separate, discrete membrane or film of polymeric material is placed in close proximity to, preferably in contact with, and more preferably adhered (e.g., heat bonded) or otherwise connected to, the geotextile fabric. A ‘coating’ of polymeric material is a continuous layer formed on the geotextile fabric, for example, by spraying the polymeric material onto the geotextile fabric. Polymeric materials coated on geotextile fabric may be present on the surface of and also impregnate into the geotextile fabric. The polymeric material may be applied on to the geotextile fabric prior to the fabric being installed on ground 100 or after. For example, referring to FIG. 9, geotextile fabric 22A can be positioned on ground 100 and secured thereto with anchor 25 and then coated with polymeric material 22B.

Examples of preferred polymeric materials on the geotextile fabric include polymeric materials that have good chemical resistance, thermal stability, and UV resistance. Suitable membranes or coatings of the polymeric material have a thickness of at least 40 mil (about 1000 micrometers or 1 mm), in some embodiments at least 60 mil (about 1500 micrometers or 1.5 mm), and in other embodiments at least 100 mil (about 2500 micrometers or 2.5 mm). Two specific examples of suitable material types include those made of polyurethane or polyurea (e.g., aromatic or non-aromatic, or aliphatic), and elastomers thereof The polymeric materials may be any of: fast set, solvent free, and VOC free. Fire rated polymeric materials are preferred in some applications. Coatable polymeric materials generally are liquid until applied to the geotextile fabric, for example by spraying such as with a spray gun (e.g., high pressure spray, plural component impingement spray gun), roll coating, flooding, painting, and the like. The resulting polymeric coating is preferably free of any pinhole or other areas where fluid may pass through. A primer material may be applied prior to application of the polymeric material to the geotextile fabric.

Two specific examples of suitable material for a coating on the geotextile fabric are commercially available from Nukote Coating Systems International under the trade designations “Nukote ST” and “Nukote FR”. Both of these specific examples are two-component, 100% solids, pure polyurea material, and can be applied to the geotextile fabric by spraying (for example, with a spray gun), painting, or roll coating.

After being applied to the geotextile fabric, the Nukote ST and Nukote FR coatings have the following parameters:

TABLE 2 Nukote ST Nukote FR Solids by volume  100%  100% Volatile organic compounds 0 gram/liter 0 gram/liter Tensile strength (ASTM D 18-23 MPa 11-13 MPa 412 C) Elongation (ASTM D 412) 350-450%   40-50%  Hardness (ASTM D 2240) 45-55 Shore D 45-55 Shore D Flexibility (2 mm mandrel Pass Pass ASTM 1737) Water vapor permeability 0.00036 perm-in — (ASTM E 96) Water absorption - 24 hours <0.5% <0.5% (ASTM D 471) Crack bridging @ −25° C. Pass Pass (ASTM C 836), 25 cycles Tear strength (Die C, ASTM 75-80 kN/m 60-65 kN/m 412) Impact resistance >20 J >20 J Abrasion resistance (ASTM D <15 mg loss 25 mg loss 4060) (Taber CS 17 wheel, 1 kg/1000 rev)

Other suppliers of polymeric material suitable for use with geotextile fabric include Rhino Linings Corp., U.S. Fabrics Inc., Specially Products Inc., and VersaFlex Inc., Custom Linings Inc. and Willamette Valley Company.

Systems according to this invention, such as systems 10 and 20, can be used in any application where controlled fluid flow is desired. For example, the systems of the present invention inhibit the mixing of two different fluid streams, such as the mixing or commingling of two gases (e.g., oxygen and methane), or the mixing or commingling of a gas with a liquid (e.g., methane and water). Additionally, the systems of the present invention can provide subterranean fluid control, both venting of gases and drainage of liquid.

One particular application for the systems of this invention is coal mining operations. In many mining operations, coal-seam-gas problems exist, caused by water (with dissolved oxygen therein) penetrating an open cut coal mine. The co-mingling of the oxygen and methane gas within the mine can cause spontaneous combustion, which once started, is almost impossible to stop. Not only can the burning methane gas ignite the coal, which is the resource the mine is trying to extract, but the fire, smoke and off-gases are a major occupational health and safety risk to workers. The fire can undercut the surface of the mine, thus weakening the roads to the point where access roads are no longer safe for mining equipment and vehicles. The systems of the present invention essentially waterproof the coal seam as well as encapsulate the area reducing the probability of spontaneously igniting methane. In addition to inhibiting oxygen from entering the ground from the aboveground atmosphere (e.g., via water), natural methane bleeding from the ground will displace and/or deplete any oxygen trapped under the geotextile material of the system.

For coal mining and other mining or extraction operations, the systems of this invention may be installed in the following manner The expanse of ground to be covered is identified and preferably cleared of any large obstacles such as boulders, rocks, logs and trees, and other obstacles that might hinder the placement of the geotextile material onto the ground or that may puncture or tear the material. It is not necessary that the expanse of ground to be covered is horizontal; a sloped expanse to be covered is acceptable. The cleared ground may be compacted and/or a layer of clay, sand or gravel may be placed on the cleared ground. After the ground has been adequately prepared, an array of perforated pipe is positioned across the expanse. The pipe may be wrapped with geotextile fabric prior to or after installation; the pipe may be wrapped the entire periphery or only a portion thereof. Geotextile material is applied over the pipe, with apertures through the material for receiving vents connected to the pipes. As indicated, the geotextile material is a combination of geotextile fabric and polymeric material. The geotextile fabric may be spread over the pipe and then polymeric material applied over the fabric. If the polymeric material is a discrete membrane, the membrane may be unfolded or unrolled over the fabric, optionally with an adhesive to adhere the polymeric material to the fabric. If the polymeric material is a coating, liquid polymeric material may be applied to the geotextile fabric, for example, by spraying, rolling, flooding, or otherwise applying the polymeric material onto the fabric. For many mining operations, liquid coating of fire rated polyurea is preferred. Anchors, to hold the geotextile material into the ground and decrease occurrence of material shifting, may be installed through the material (i.e., through the geotextile fabric and the polymeric material) or may be installed through the geotextile fabric prior to application of the polymeric material. After the geotextile material has been installed and optionally anchored, ballast material, such as rocks, dirt, gravel, etc. may be placed on the geotextile material or the material may remain uncovered. To facilitate collection and venting of gas from below the geotextile material, vents are preferably positioned at high elevation locations in the system (either locally high areas or overall high areas). Gas diffusing up from the covered ground will be directed by the geotextile material to the perforated pipes, which then direct the collected gas to a vent. The vents may include any of the features described above, such as safety release valve, one-way valve, wind powered venting system, etc.

In an alternate installation, the array of perforated pipes under the geotextile material may be eliminated. In such a system, gas diffusing up from the covered ground will be contained by the geotextile material and preferably directed to a vent by the material.

The systems described above provide a barrier between subterranean fluids present below the geotextile material, and fluids present above the geotextile material. Such as system is particularly adapted in inhibiting the seepage of water (e.g., rain) into methane-containing subterranean regions.

Another particular application for the systems of this invention is land fills. Many landfills attempt to extract the methane gas being created subterraneously within the landfill by the decomposition of garbage and utilize the methane, for example, as a power generating source. The gas impermeable geotextile material of this invention traps the evolving methane and diverts it to the fluid distribution system (i.e., the pipes, vents, etc.) where the methane can be collected and harvested. After a period of time after the landfill has lapsed active use, the ground is sufficiently settled to support buildings and other structures. However, although physically stable, the ground could still generate methane. The systems of this invention provide a barrier and trap existing and evolving methane and vent it to a safe location, away from the building or where persons may frequent.

For landfill operations, the systems of this invention may be installed in the following manner. An area of garbage (or other compostable or methane-generating material) is identified and preferably prepared to provide a surface free of any obstacles that might hinder the placement of the geotextile material onto the ground or that may puncture or tear the material. It is not necessary that the expanse of area to be covered is horizontal; a sloped expanse to be covered is acceptable. The cleared area may be compacted and/or a layer of clay, sand or gravel may be placed on the cleared area. After the area has been adequately prepared, an array of perforated pipe is positioned across the expanse. The pipe may be wrapped with geotextile fabric prior to or after installation. Geotextile material is applied over the pipe, with apertures through the material for receiving vents connected to the pipes. As indicated, the geotextile material is a combination of geotextile fabric and polymeric material. The geotextile fabric may be spread over the pipe and then polymeric material applied over the fabric. If the polymeric material is a discrete membrane, the membrane may be unfolded or unrolled over the fabric, optionally with an adhesive to adhere the polymeric material to the fabric. If the polymeric material is a coating, liquid polymeric material may be applied to the geotextile fabric, for example, by spraying, rolling, flooding, or otherwise applying the polymeric material onto the fabric. Anchors, to hold the geotextile material into the ground and decrease occurrence of material shifting, may be installed through the material (i.e., through the geotextile fabric and the polymeric material) or may be installed through the geotextile fabric prior to application of the polymeric material. To facilitate collection and venting of gas from below the geotextile material, vents are positioned at the perimeter of the system, at elevationally high locations, or both. Gas (e.g., methane) being generated by the decomposing garbage will be directed by the geotextile material to the perforated pipes, which then direct the collected gas to a vent. The vents may include any of the features described above, such as safety release valve, one-way valve, wind powered venting system, etc. Ballast material, such as clean fill, dirt, sand, rock, gravel, and the like may be placed over the system. In some applications, ballast material may include methane producing material (e.g., garbage). As more garbage accumulates, subsequent layers of garbage and geotextile material can be stacked to provide alternating garbage and subterranean fluid flow systems. Multiple systems may be fluidly connected to utilize the same vents.

The systems described above provide a containment barrier for subterranean fluids present below the geotextile material. Such as system is particularly adapted in inhibiting the uncontrolled diffusion of gas (e.g., methane).

It is understood that numerous variations of the geotextile material system could be made while maintaining the overall inventive design of the system and remaining within the scope of the invention. Numerous alternate design or element features have been mentioned above. Other alternate designs include, for example, geotextile materials 12, 22 described above are impervious to both liquid and gas. In alternate embodiments according to this invention, the geotextile material is impervious to liquid but selectively impervious to gases; for example, smaller gas molecules may pass through the geotextile material while larger gas molecules (e.g., hydrocarbons) are halted. As another example, the systems of this invention may include a scavenger (such as an ion exchange resin, sodium bisulfate, carbon media (e.g., activated carbon), zeolites, molecular sieves, getters, clays, silica gels, superacids and/or heteropolyacids, nanosorbents, nanotubes, and metal oxides) to capture and retain fluid. As another example, systems of this invention may be used to control seepage of contaminated or otherwise undesirable liquid out from the ground.

Thus, embodiments of the SYSTEM FOR FLUID CONTAINMENT AND VENTING are disclosed. The implementations described above and other implementations are within the scope of the following claims. One skilled in the art will appreciate that the present invention can be practiced with embodiments other than those disclosed. The disclosed embodiments are presented for purposes of illustration and not limitation, and the present invention is limited only by the claims that follow. 

What is claimed is:
 1. A system for controlling subterranean fluid flow, the system comprising: a fluid impervious geotextile sheet material comprising geotextile fabric having a first side and a second side, the geotextile sheet material having a continuous polymeric material thereon, the polymeric material optionally being on the second side of the geotextile fabric; and a fluid distribution system comprising an array of perforated pipes in fluid communication with a vent, wherein when the system is installed, the fluid impervious geotextile sheet material laterally extends on or under the surface of the ground with the first side of the geotextile sheet material more subterranean than the second side, wherein the array of perforated pipes is located under the geotextile sheet material at a location to collect and vent volatile gases captured under the fluid impervious geotextile sheet material.
 2. The system of claim 1, wherein the fluid impervious geotextile sheet material is configured to provide at least one sloped surface, and a portion of the array of perforated pipes is located at a top location of the sloped surface under the fluid impervious geotextile sheet material.
 3. The system of claim 1, further comprising a plurality of geotextile anchors.
 4. The system of claim 1, comprising geotextile fabric wrapped around the array of perforated pipes.
 5. The system of claim 1, the vent having a one-way valve or a safety release valve.
 6. The system of claim 1, further comprising a powered venting system.
 7. The system of claim 6 wherein the powered venting system is wind powered.
 8. The system of claim 1, further comprising a gas probe.
 9. The system of claim 1, wherein the geotextile sheet material is installed over a methane generating material.
 10. The system of claim 9 wherein the methane generating site is a landfill.
 11. The system of claim 1, wherein after being installed, the geotextile sheet material is covered by ballast material.
 12. A method of controlling fluid flow in ground, the method comprising: installing a system of claim 1 laterally over an expanse of ground with the first side of the geotextile material against the ground; optionally covering at least a portion of the system with ballast; collecting fluids, optionally volatile fluids, from the ground underneath the geotextile sheet material in the fluid distribution system; and venting collecting gases.
 13. The method of claim 12 wherein the collected gas comprises methane.
 14. The method of claim 13 wherein the methane is collected for subsequent use as fuel.
 15. The method of claim 12 wherein the system is installed over a coal seam. 